Seagate Reportedly Bids for TDK's Disk-Head Business; Shares Fall 9%

Four days ago, a factory story knocked hard-drive stocks down.

On Tuesday, a component story did it again.

The component is the read-write head. Only one company in the world makes it independently: the Japanese electronics maker TDK.

What Bloomberg Reported, What Toshiba Said

Citing unnamed sources, Bloomberg reported that Toshiba began talks with TDK this spring to buy the head business. Over the summer, Seagate joined with a higher offer.

The price under discussion is several billion dollars. TDK wants to exit this low-return business and shift toward batteries, sensors and passive components.

According to secondary reports, the story also said executives from the three companies met in Tokyo last week to discuss future head supply and a possible joint venture.

Toshiba pushed back the same day. It said the report was "inconsistent with the company's understanding of the situation" and denied that any three-way talks had taken place. Japan Industrial Partners, Toshiba's owner, said much the same.

Seagate and TDK did not comment.

So there is no signed deal, no exchange filing and no confirmed bid. There is a newspaper report and one party disputing part of it.

Who Makes the Heads

Every platter spinning inside a hard drive has two surfaces. A head sits over each surface, writing and reading the data.

Seagate and Western Digital make most of their own heads and turn to TDK when demand peaks. Toshiba has no head production of its own. It buys all of its heads from TDK, including the next-generation heads needed for heat-assisted magnetic recording, or HAMR.

TDK's segment that includes heads posted ¥81.6 billion in sales in the April-June quarter, up 49.6% from a year earlier. The company said head unit volume rose 36%.

Toshiba holds about 10% of the market, according to TrendForce. Last week's report said it plans to double that capacity within its fiscal 2027; details are in our earlier story.

The headline was about an acquisition.

What the market priced was a bottleneck.

No Heads, No Drives

Capacity plans are usually described in terms of buildings. But whether a drive gets built depends on its scarcest part.

That arithmetic explains both outcomes.

If Toshiba wins, it takes control of the missing piece of its capacity plan. On Oct. 2, a Citi analyst raised exactly this objection: Toshiba sources critical components externally, which could limit any real capacity gain.

If Seagate wins, it controls its rival's only source of heads. Wedbush analyst Matt Bryson said that would leave the third-largest drive maker dependent on Seagate, making antitrust approval harder. Bloomberg also noted that data-center storage is seen as strategic for economic security, so a deal would likely face close review.

Both paths share one thing. Head supply is no longer quiet background; it is now a bargaining chip.

What Happened on Tuesday

The story broke during the Asian session. TDK rose more than 7% intraday in Tokyo and traded around 5.2% higher.

In New York, Seagate closed down 9.2% at $805.63 and Western Digital down 6.9% at $411.20. Seagate is about 15% below its Oct. 1 close.

The selling stayed inside disk drives. Memory maker Micron traded flat during the session, and the S&P 500 closed at a record. Seagate's past month shows the level this drop came from.

The broader market, meanwhile, moved higher over the same week.

The Part That Doesn't Fit

Most analysts called the selling excessive. Morgan Stanley, Bernstein, Citi and Evercore wrote that Toshiba's Philippines expansion is not enough to meaningfully loosen tight supply of data-center drives. Goldman Sachs kept its Hold rating, warning that added capacity could weaken pricing power and margins over the medium term.

Pinning all of the selling on this report would also overstate it. Both stocks had run up sharply this year; Seagate had roughly tripled before Tuesday. At that level, even a small uncertainty can trigger heavy selling.

What Remains

There is no deal. There is a meeting one company denies and silence from the other two.

But the assumption propping up hard-drive margins has now been questioned twice. The first time, the question was whether Toshiba would build a factory. This time, it is who will supply that factory's parts. For how valuations hang on assumptions like these: How Valuation Works

This story draws on secondary reports of Bloomberg's Oct. 6 article by Investing.com, TrendForce and other outlets, Toshiba's same-day response, TDK's first-quarter fiscal 2027 presentation and Oct. 6 closing data. Details of the acquisition talks rely on unnamed sources; Seagate and TDK did not comment. The Tokyo meeting detail appears only in secondary reports. The market value loss is an approximate figure calculated from closing prices and published market capitalizations. The head-count example in the mechanism section is illustrative; Toshiba has not disclosed its actual unit output.